Baseline and incident hypochloremia in chronic heart failure outpatients: Clinical correlates and prognostic role

•Baseline chloride serum levels and hypochloremia were independently associated with an increased risk of mortality and hospitalizations due to acute decompensated heart failure.•During follow-up, high baseline diuretic dose was the main determinant of the occurrence of hypochloremia.•Also the occurrence of hypochloremia during follow-up was independently associated with a greater risk of death.•In our series of chronic heart failure outpatients, low chloride serum levels have been detected in ten percent of available measurements.•Hypochloremia was more frequently observed than hyponatremia and showed an independent prognostic value also from it. Electrolyte serum disorders are associated with poor outcome in chronic heart failure. The aim of this study sought to identify the main driver of incident hypochloremia in chronic HF (CHF) outpatients and to determine the prognostic value of baseline and incident hypochloremia. Consecutive CHF outpatients were enrolled and clinical, laboratoristic and echocardiographic evaluations were performed at baseline and repeated yearly in a subgroup of patients. Baseline and incident hypochloremia were evaluated. During an up to 5-year follow-up, all-cause mortality was the primary end-point for outcome. Among 506 patients enrolled, 120 patients died during follow-up. At baseline, hypochloremia was present in 10% of patients and it was associated with mortality at univariate (HR: 3.25; 95%CI: 2.04–5.18; p